The present invention disclosed herein relates to a dual-polarized dipole antenna including a plurality of dipole antennas generating dual-polarized waves.
Mobile communication has been developed from a first generation advanced mobile phone system (AMPS), by way of digital communication and 3rd generation communication capable of transmitting large capacity data, to 4th generation communication capable of accessing a wide band communication network. As a service provider provides various mobile communication services including 2G, 3G, and long term evolution (LTE), etc., an antenna of a mobile communication base station becomes bandwidth-enhanced and miniaturized. In particular, in 4th generation mobile communication typified by a worldwide interoperability for microwave access (WiMAX) and LTE, a remote radio head (RRH) technology, which is a next generation transmitter and receiver, is expected to be widely used.
Typically, an antenna performs a role of radiating an electromagnetic wave to the outside or receiving an electromagnetic wave from the outside in wireless communication. In detail, an antenna performs a role of converting an electrical signal input from a feed line into an electromagnetic wave and radiating the electromagnetic wave to the outside, and receiving an electromagnetic wave from the outside through half wavelength resonance, converting the electromagnetic wave into an electric signal and delivering the electric signal to the feed line.
There are various antennas according to operating method and specification thereof. Among them, a dipole antenna is an antenna symmetrically distributing electric field lines around a central axis, when an AC current is applied to an open microstrip line.
Such a dipole antenna is mainly used in a base station for a mobile communication system and implemented in various types. In particular, a dual-polarized antenna has a square dipole structure in which two pairs of dipole antennas are symmetrically arrayed, or a cross dipole structure in which two dipole antennas are extended in straight lines and arrayed to cross each other. The dipole antenna pairs may be arrayed orthogonally to each other and used for transmitting and receiving two polarized signals.
Core technology of a miniature mobile communication base station antenna lies is in miniaturization by embedding a RF portion and an antenna in a small cube. In order to increase channel capacity, a dual-polarized antenna may be used by using an electric/magnetic field, and, when the antenna is inserted into the cube, boundary surface conditions may be changed such that antenna characteristics may be changed. As the result, antenna bandwidth and gain may be reduced. Accordingly, manufacturing a miniature mobile communication base station antenna having a wide bandwidth, high isolation characteristics, and a high gain is emerged as an important issue.